Very noisy render with emission+glossy shader
this is a very complex topic and would be to much for a single post answer. but i am trying to give you a rough understanding about what you have to change:

In the virtual space, everything is about faking. not about recreating the real world. this means that it only has to look real from the field of view, but everything else does not matter.

This means: remove everything that does not matter. you do not need a complete interior, remove the all walls that are not visible to the eye. this way every sample that would bounce against the wall, now flies into infinity and does not produce more bounces (that would slow down your render). 

also: do NEVER (if possible) light your scene whit mesh light. mesh light is way slower and produces much noise. again, just fake it! in the most cases nobody will notice that you only put a single spotlight there (make sure that multiple importance is activated in the lights material settings). the bigger the light source, the less noise.

also some technical stuff. set the render settings as followed:
sampling: set "clamp direct" and "inderect" to 9.
light paths: "filter glossy" to 0.5-2 (higher values mean less noise but more blury pictures).